Method and apparatus for producing fire extinguishing foam



May 24 H. B URMEISTER METHOD AND APPARATUS FOR PRODUCING FIR E EXTINGUISHING FOAM Filed June 10 Patented May 24, 1932 UNITED STATES earen'rvorsice HANS BUBIVIEISTER, OF BERLIN, GERMANY, ASSIGNOR, BY DIRECT AND MESNE AS- SIGNMENTS, TO PYRENE-EIINEMAX CCRPOR ATIQN. A GOR'EORATIGN OE DELAWARE generated.

METHOD AND APPARATUS FOR PRODUCING FIRE EXTINGUISHI'NG- FOAIVI Application filed June 10, 1925, Serial No. 115,089, and in Germany July 30, 1925.

My invention relates to an improved method and apparatus for producing fire extinguishing foam briefly called firefoam.

It is already known to store the chemicals 1 necessary for producing firefoam at the bottom of a tank below the combustible liquid and to apply to it water which causes the reaction of the chemicals and the generation of the foamwhen required.

In contrast herewith my method consists in storing the substances serving for the generation of the foam mixed together in a closed receptacle and generating the foam in this receptacle by applying water under pressure to the chemicals.

Particular difficulties arose in the carrying out of this method in the choice of the chemicals and in overcoming the difliculties of operation during the generation of the foam.

The difficulty in the choice of the chemicals is according to my invention eliminated by producing such chemicals which possess practically no humidity to cause a reaction between the chemicals. For example where an acid constituent such as aluminum sulfate is employed as one of the foam producing elements, it may advantageously be more or less completely dehydrated before introduction into the container wherein the foam is to be This dehydrated material when mixed with dry sodium carbonate, or similar alkaline constituent, will have no tendency to cake up so long as moisture is excluded and the mixture will react readily to produce foam when water is added. It will be underfoam has also successfully been overcome is illustrated in the drawings aflixed hereto.

In Fig. 1 of the drawings the apparatus is shown in longitudinal section.

Fig. 2 is a plan view of a spray head and its spray pipes;

Referring to the drawings, a is a closable receptacle in which the chemicals required for the generation of the foam are stored mixed together. The water under pressure passes through a pipe 2' into the receptacle or container-a and causesfhere the reaction of the chemicals upon one another and thus the generation of the foam. To bring about a uniform dissolution of the chemicals a spraying head 6 with a plurality of spray pipes Zis provided which force the water in a strong jet andwith a gyrating motion into the chemicals. The spraying head and the end of the discharge pipe d shouldbe located at the lowest pointof the apparatus. V

When the water enters the mixture of chemicals, carbon dioxide is formed. The larger portion of the gas is detained by the foamand led away by the discharge piped. A small portion of the gas, on the otherha-nd,

fills in a short time the hollow space in they container or receptacle a between and above the chemicals. Since the receptacle or contamer a is firmly closed at the top, this portion of the carbon dioxide gas is unable to escape and fills duringthe operation of the apparatus. the entire space down to the ap proximate level of the lower end of the'pipe (Z. Inthis way the result is attained that the chemicals in the receptacle or container a remain during the operation permanently dry above the lowest end of the pipe 03. Owing to this dry storage the internal resistance of the chemicals against the foam generated becomes so low that the chemicals sink continuously and uniformly down towards the bottom.

It is obvious that due to this gas separation and storage only a. very small space of the container a is wetted by the water and shows only minute remainders of foam or humidity when the apparatus is stopped.

Owing to this developmentof gas the ap paratus may be so constructed that it may purpose the apparatus has been subdivided and possesses an upper chamber or compartment n which is adapted to .be closed in an airtlght manner from outslde by means of a flap 0. la is an airtight cover through which the chemicals are charged into .the upper chamber. For the purpose of'balancing the pressure in the lower and the upper compartment, a connecting pipe 9 with stopping device r is provided. As soon as the contents of the upper chamber a hasbeen emptied into the lower, the flap is closed as well as the valve 1 or the like. Thecover is can now be opened and fresh chemicals may be introduced into the apparatus through it.

. After closure'of the cover 1 0. the stop valve r is opened so that fresh carbon dioxide gas passes from the lower chamber into the upper chamber n. Then the flap door 0 is opened so that the chemicals are able to flow along the walls of the funnel p into the lower chamber. Below the fiapdoor 0 is provided a distributor s for the chemicals dropping down from the funnel.

c is a nozzle which may either serve to dilute the mixture produced by additional 5 but which may equally well be arranged inside the receptacle or container. By'this by-pass fresh water is discharged from the outlet pipe f on to the stored chemicals. In this manner a reaction of the chemicals at the top of the apparatus is attained in a short time. By the gas and foam. generation a pressure is. set up here, which, however, is not greater than the pressure of the water in the mains. By this arrangement a difierence of pressure is set up in the upper part of the opparatus and at the level of the discharge'pipe at the spray nozzle 0. The excess pressure'prevailing in theupper part of the apparatus has the effect that the chemicals stored in the dry state are continuously fed towards the bottom of the apparatus which ensures a uniform generation of foam.

h is an additional water nozzle in the foam Withdrawing pipe to enable the viscosity of the foam to be controlled as desired. If the nozzle 0 is so dimensioned that with the valve 9 closed a foam as tough and thick as possible is generated, the quality of the'foam may be changed by opening the valve 9 more or less, so that by the introduction of additional water into the foam discharge pipe the foam.

can be made as thin as desired.

It will be understood by those skllled n the art that varlous modifications maybe made in the method and apparatus without particularly for fire extinguishing purposes,

which consists in storing the substances serving for the generation of the foam mixed together in a closable container, introducing water continuously under line pressure into said container to produce the fire foam in said container, and discharging the. foam from said container under line pressure and the gas pressure developed within said container.

2. The method of producing foam, more particularly for fire extinguishing purposes, which consists in storing in a closable container a mixture of foam-producing substances which possesses practically no moisture, introducing water under linerpressure into said container at a definitepoint, gradually bringing the mixture and water together at said point, whereby said water will react with only a portion of said mixture at a time, and removing the foam produced by the reaction under pressure. 7

3. The method of producing foam, more particularly for fire extinguishing purposes, which consists in storing in a closable container a mixture of foam-producing substanceswhich possesses practically no moisture and a moisture-absorbing constituent, introducing water under line pressure into said container at a definite point to react with only a portion of said mixture at a time as they are graduallybrought together, and removing the foam produced by the reaction under pressure.

4C. In an apparatus for producing fire foam, a closed receptacle in which the chemicals required for the generation of the foam uniformly mixed are stored in the dry state, a pipe-opening into said receptacle adapted to be connected to a line carrying water under pressure, means connected with said pipe for distributing the water over a limited por;

tion of said chemicals thus toproduce said foam, and an outlet adjacent said means to discharge the foam.

5. In an apparatus for producing lire foam, a closed receptacle in which the chemicals required for the generation of the foam uniformly mixed are stored in thedry state and a pipe opening into said receptacle for adding water under pressure to said chemicals and thus to produce the said foam, an outlet for foam adjacent said pipe, a closable chamber in communication with said receptacle adapted to permit the recharging of said apparatus during service, and means for equalizing the pressures in saidreceptacle and chamber.

-6. In an apparatus for producing fire foam,

a closed receptacle in which the chemicals.

required for the generation of foam are stored uniformly mixed in a dry state, a pipe opening into said receptacle for adding water under pressure to said chemicals to produce foam, said receptacle comprising an upper chamber and a lower chamber to permit recharging of the apparatus during service and a by-pass arranged to connect the upper part of the upper chamber with the lower chamber to balance the pressures to facilitate feed of recharging chemicals from the upper chamber to the lower chamber.

7. Apparatus for producing foam for fire extinguishing purposes comprising a container for uniformly mixed foam forming chemicals, a discharge conduit for foam leading from said container, said conduit having an intake opening directed away from the center of said container, an inlet for water within said container terminating in a nozzle alined with an opening in said conduit and arran ed to act as an ejector.

8. Xpparatus for producing foam for fire extinguishing purposes comprising a container for uniformly mlxed foam forming chemicals, an outlet means for foam leading upward within said container from a point adjacent its bottom to a point of use, and means adjacent the bottom of said container arranged to direct a jet of water over a local area at the bottom of the container and another jet of water into the foam outlet.

9. Apparatus for producing foam for fire extiguishing purposes comprising a container for uniformly mixed foam forming chemicals, a discharge conduit for foam leading from said container, a plurality of nozzles arranged to direct jets of water into said container adjacent the bottom of the charge of chemicals therein and an opening in said conduit alined with one of said nozzles together with an inlet at the top of said container to admit water above said foam forming chemicals.

10. Apparatus for producing foam for fire extinguishing purposes comprising a con tainer for uniformly mixed foam forming chemicals, a discharge pipe for foam extending from near the bottom of said container upwardly and having a restricted portion, and a nozzle alined with said discharge pipe and cooperating with the restricted portion to form an ejector.

11. Apparatus for producing foam for fire extinguishing purposes comprising a container for uniformly mixed foam forming chemicals,'a discharge pipe for foam extending from near the bottom of said container upwardly and having a restricted portion, a nozzle alined with said discharge pipe and cooperating with the restricted'portion to form an ejector, and a plurality of nozzles surrounding the first mentioned nozzle.

12. Apparatus for producing foam for fire extinguishing purposes comprising a container for uniformly mixed foam forming chemicals, a discharge pipe for foam extending from near the bottom of said cona point spaced from but relatively near the bottom of said container and having a restricted portion, an upwardly directed nozzle alined with said outlet pipe and cooperating with the restricted portion to form an ejector, and an auxiliary nozzle to direct a stream of water into the charge of foam forming chemicals. 1 r

14. Apparatus for producing foam forfire extinguishing purposes comprising a stationary container for a charge of uniformly.

mixed foam forming chemicals, an outlet pipe for foam having its intake spaced from but near the bottom of said container and facing the same, a nozzle'directed upwardly into said outlet pipe, the nozzle and outlet pipe being formed to constitute an ejector, and an auxiliary nozzle adjacent the bottom of the container and adjacent the intake to said outlet for directing a stream of water into the bottom portion of the charge of foam forming chemicals.

15. Apparatus for producing foam for fire extinguishing purposes comprising a stationary container for a charge of uniformly mixed foam forming chemicals, an outlet pipe for foam extending from a point near the bottom of said container, andhaving its intake opening directed away from the main body of said charge, a nozzle alined with said outlet pipe, the outlet pipe and nozzle being formed to constitute an ejector, and an auxiliary inlet for leading water to said container at a point near the top of said charge.

l6. The method of producing foam, more particularly for fire extinguishing purposes, A

which consists in storing in a closable con- 7 tainer a mixture of foam-producing substances, introduclng water under line pressure lnto said container near its bottom, gradually feeding the mixture into the water so that the latter will react with only a portion of said mixture at a time, and removing the foam produced bythe' reaction under pressure. I V r 17. The method of producing foam, more particularly for fire extinguishing purposes, which consists in storing in a closable con tainer a mixture of foam-producing sub-- stances which possesses practically nomoisture, introdu'cing'water under line pressure into said container to react'with only a por- 7 tion of said mixture at a time, and removing the foam produced by-the reaction under the pressure produced by .the reaction assisted by the movement of Water under line pressure.

18. In an apparatus for producing fire foam a closable container adapted to receive a mixture of foam forming chemicals, a series of jets at the bottom of said container adaptedto direct water into the bottom portion of said mixture, means for connecting said jets to a Water line, means for removing the foam as it is developed at the bottom of said container said means comprising a duct leading upward through said container to a point of use and means for directing Water from said line into said foam removing 19, In an apparatus for producing fire foam a closablecontainer adapted to receive a mixture of foam forming chemicals,'a se- 7 ries of jets at the bottom of said container adapted to direct Water into the bottom portion of said mixture, means for directing Water into said container adjacent the top, an outlet adjacent the bottom of the container-for theremoval of the foam developed,

7 means for directing Water into said outlet to assist in the removal of the foam, and

means adapted to be connected at a single point to a Water line for delivering Water to said jets and to the two mentioned Water directing means.

In testimony whereof I aflix my signature.

HANS BURMEISTER. 

